In radiation therapy and chemotherapy of cancer, the detrimental side effect of the therapy on the bone marrow and its functions often constitutes the dose-limiting factor. The bone marrow performs vital functions in the production of red blood cells, white blood cells, and blood platelets. The red blood cells are cells that carry oxygen to all the organs and tissues of the body. The white blood cells are responsible for fighting infection caused by germs. The blood platelets are small, disc shaped cells in the blood that are needed to form blood clots to control bleeding and bruising. Radiation therapy and chemotherapy often causes a reduction in the number of white blood cells, increasing the risk of the person of developing an infection. Likewise, a reduction in blood platelets may affect blood coagulation and hemostasis. Without a minimum function of the bone marrow, no medical patient can survive for a prolonged period of time. Bone marrow depression is an abnormal condition characterized by the inability of the bone marrow to produce normal amounts of white blood cells, red blood cells and platelets, and is as mentioned above a detrimental side effect in radiation therapy and chemotherapy. Accordingly, while higher doses of a chemical agent and/or radiation usually have greater anti-tumor effects, the imperative requirement to maintain bone marrow function imposes limits to applicable dose. The residual bone marrow reserve, i.e. the degree to which the bone marrow is able to continue functioning and to recover from damage as for instance inflicted by radiation therapy and chemotherapy, is subject to strong interpatient variability. It moreover depends on the treatment history of the patient.
In current therapy modalities, a wide safety margin in the administered dose of anti-tumor agents like radiation and/or a chemical medication has to be observed in order to ensure avoidance of bone marrow failure, even if this means for the majority of patients a significant reduction in the probability with which the therapy will achieve tumor control. Hence, an improved apparatus, method, computer-readable medium, and use for therapy planning would be advantageous.